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Guarana Research

Scientific publications dating back to 1872 document the medicinal properties of Paullinia cupana, also known as guarana. Today, however, this herbal extract is primarily thought of as a caffeine source commonly used in “energy drinks”. Unfortunately, this form of reductionism is all too common. Modern medicine often times focuses on a specific attribute of any given food or remedy. Oranges are a good source of Vitamin C. Red wine contains resveratrol, an age-defying antioxidant. Oats provide a cholesterol-lowering pop of soluble fiber. All of these assertions are valid, but leave a lot by the wayside.

My philosophy is that herbal extracts should be considered in a holistic manner. Their chemical composition and the approximate quantities of active ingredients always need to be taken into account. Additionally, the interaction between the various phytochemicals in herbs can also influence the effects of herbal remedies. For instance, guarana seeds possess many naturally occurring chemicals, including catechins, methylxanthines (caffeine, teophylline and theobromine) and procyanidins. According to a recent experiment, the complex interplay between these chemicals may account for guarana having a more potent stimulant effect than caffeine alone.

If guarana was only an energy enhancer, I probably wouldn’t devote a column to it. But, much like chocolate, coffee and green tea, guarana imparts many other health benefits beyond a simple stimulant boost.

Guarana and Cancer Support - Two studies report that guarana mitigates some of the side effects associated with chemotherapy treatment. Specifically, it reduced fatigue without affecting anxiety, depression or sleep quality. Other trials reveal that 50 mg daily of a guarana extract improves appetite in patients with advanced cancer and decreases the severity of hot flashes in breast cancer patients.

Guarana for Cognition and Mood - A multi-vitamin-mineral formula with 300 mg guarana (Berocca) has been found to benefit cognitive functioning and mood in three separate studies. The supplement not only decreased mental fatigue, but also activated areas of the brain “associated with working memory and attentional processing” and enhanced “decision-making performance”. Other research indicates that combining 75 mg guarana with 200 mg ginseng benefits cognitive processing speed. It’s interesting to note that the 75 mg extract of guarana only contained a very small amount of caffeine (9 mg).

Guarana, Cardiovascular Health and Mortality -Stimulants, natural or otherwise, are typically associated with cardiovascular risk. So, for some, it may be surprising to know that populations that habitually consume guarana tend to show a lower risk of cardiometabolic diseases such as hypertension, metabolic syndrome and obesity. Antioxidant-rich herbal remedies (coffee, dark chocolate, green tea, yerba mate) are often correlated to cardiovascular protection. In the case of guarana, at least two known mechanisms may explain the noted cardioprotective effect: 1) polyphenols in guarana seeds reduce LDL cholesterol oxidation, a contributor to hardening of the arteries; 2) guarana may decrease the likelihood of abnormal blood clotting (thrombosis) due to its anti-platelet aggregatory activity.

When considering a guarana extract, I recommend choosing products that are standardized for caffeine content. Whenever you’re dealing with a stimulating substance, quality control is especially important. To date, guarana has a good toxicity record and a long history of safe, traditional use. Still, the possibility of adverse reactions exist if proper checks and balances aren’t employed in the production process. So, ask manufacturers questions and read labels carefully to ensure that you derive the benefits of guarana while sidestepping the potential risks.

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

To learn more about the studies referenced in today’s column, please click on the following links:

Previous studies suggested that certain plants, such as guarana (Paullinia cupana), exert a protective effect against cancer-related fatigue in breast cancer patients undergoing chemotherapy. However, guarana possesses bioactive molecules, such as caffeine and catechin, which may affect the pharmacological properties of antitumor drugs. Therefore, the aim of this study was to evaluate the effects of guarana on breast cancer cell response to 7 chemotherapeutic agents currently used in the treatment of breast cancer. To perform this study, MCF-7 breast cancer cells were cultured under controlled conditions and exposed to 1, 5 and 10 µg/ml guarana concentrations, with and without chemotherapeutics (gemcitabine, vinorelbine, methotrexate, 5-fluorouracil, paclitaxel, doxorubicin and cyclophosphamide). The effect of these treatments on MCF-7 cell viability and proliferation was spectrophotometrically analyzed with the MTT assay. The main results demonstrated an antiproliferative effect of guarana at concentrations of 5 and 10 µg/ml and a significant effect on chemotherapeutic drug action. In general, guarana improved the antiproliferative effect of chemotherapeutic agents, causing a decrease of >40% in cell growth after 72 h of exposure. The results suggested an interaction of guarana with the chemotherapeutic drugs, which requires confirmation by in vivo complementary studies.

Advanced glycation end-products (AGEs) are considered potent molecules capable of promoting neuronal cell death and participating in the development of neurodegenerative disorders such as Alzheimer’s disease (AD). Previous studies have shown that AGEs exacerbate β-amyloid (Aβ) aggregation and AGE-related cross-links are also detected in senile plaques. Acrolein (ACR) is an α, β-unsaturated aldehyde found in the environment and thermally processed foods, which can additionally be generated through endogenous metabolism. The role of ACR in AD is widely accepted in the literature. Guarana (Paullinia cupana Mart.) is popularly consumed by the population in Brazil, mainly for its stimulant activity. In the present study, we showed that guarana (10, 100, and 1000 µg/mL) is able to prevent protein glycation, β-amyloid aggregation, in vitro methylglyoxal, glyoxal, and ACR (20 μM)-induced toxicity on neuronal-like cells (SH-SY5Y). Since these are considered typical AD pathological hallmarks, we propose that guarana may deserve further research as a potential therapeutic agent in such a neurodegenerative disease.

Effects of bioactive constituents in functional cocoa products on cardiovascular health in humans.

Cocoa manufacturers are producing novel products increasing polyphenols, methylxanthines or dietary fibre to improve purported health benefits. We attempt to explain the contribution of cocoa bioactive compounds to cardiovascular effects observed in previous studies, placing particular emphasis on methylxanthines. We focused on a soluble cocoa product rich in dietary fibre (DFCP) and a product rich in polyphenols (PPCP). Effects of regularly consuming DFCP (providing daily 10.17 g, 43.8 mg and 168.6 mg of total-dietary-fibre, flavanols and methylxanthines, respectively) as well as PPCP (providing daily 3.74 g, 45.3 mg and 109.8 mg of total-dietary-fibre, flavanols and methylxanthines, respectively) on cardiovascular health were assessed in two controlled, cross-over studies in free-living normocholesterolemic and moderately hypercholesterolemic subjects. Both products increased HDL-cholesterol concentrations, whereas only DFCP decreased glucose and IL-1β levels in all subjects. Flavanols appeared to be responsible for the increase in HDL-cholesterol, whereas insoluble-dietary-fibre and theobromine in DFCP were associated with the hypoglycemic and anti-inflammatory effects observed.

The Effects of Supplementation with a Vitamin and Mineral Complex with Guaraná Prior to Fasted Exercise on Affect, Exertion, Cognitive

Exercise undertaken in a fasted state can lead to higher post-exercise mental fatigue. The administration of a vitamin and mineral complex with guaraná (MVM + G) has been shown to attenuate mental fatigue and improve performance during cognitively demanding tasks. This placebo-controlled, double-blind, randomized, balanced cross-over study examined the effect of MVM + G consumed prior to morning exercise on cognitive performance, affect, exertion, and substrate metabolism. Forty active males (age 21.4 ± 3.0 year; body mass index (BMI) 24.0 ± 2.4 kg/m2; maximal oxygen consumption (V̇O2max) 57.6 ± 7.3 mL/min/kg) completed two main trials, consuming either MVM + G or placebo prior to a 30-min run at 60% V̇O2max. Supplementation prior to exercise led to a small but significant reduction in Rating of Perceived Exertion (RPE) during exercise compared to the placebo. The MVM + G combination also led to significantly increased accuracy of numeric working memory and increased speed of picture recognition, compared to the placebo. There were no significant effects of supplementation on any other cognitive or mood measures or on substrate metabolism during exercise. These findings demonstrate that consuming a vitamin and mineral complex containing guaraná, prior to exercise, can positively impact subsequent memory performance and reduce perceived exertion during a moderate-intensity run in active males.

METHODS: Following institutional ethical approval, twelve healthy recreationally active participants, five females and seven males, were randomized to perform two separate experimental ergometry cycling trials, and to ingest 1.5 g (3 × capsules) of either a multi-ingredient supplement (SHRED) or placebo (PL). Participants rested for 3 h, before performing a 30-min cycling exercise corresponding to their individually-determined intensity based on their maximal fat oxidation (Fatmax). Fatty acid oxidation (FAO) was determined at rest, 3 h before exercise (Pre1), immediately before exercise (Pre2) and during exercise (Post), using expired gasses and indirect calorimetry. Rate of perceived exertion (RPE) was measured every 3 min during the 30-min exercise. Additionally both mood state and perception of hunger were assessed at Pre1, Pre2 and Post exercise. A repeated measures ANOVA design and Cohen’s d effect sizes were used to analyze potential differences between times and treatment conditions.

RESULTS: FAO increased in SHRED from Pre1 to Pre2 [0.56 ± 0.26 to 0.96 ± 0.37, (p = 0.003, d =1.34)] but not in PL [0.67 ± 0.25 to 0.74 ± 0.19, (p = 0.334) d = 0.49], with no differences were found between conditions (p = 0.12, d = 0.49). However, Cohen’s d = 0.77 revealed moderate effect size in favor of SHRED from Pre to Post exercise. RPE values were lower in SHRED compared to Pl (p< 0.001). Mood state and perception of hunger were not different between conditions, with no interaction effects. However, a trend was shown towards improved satiety in SHRED compared with PL, [F(1,11) = 3.58, p = 0.085].

Bioavailability of catechins from guaraná (Paullinia cupana) and its effect on antioxidant enzymes and other oxidative stress markers in healthy human subjects.

We assessed the effects of guaraná (Paullinia cupana) consumption on plasma catechins, erythrocyte antioxidant enzyme activity (superoxide dismutase, catalase and glutathione peroxidase) and biomarkers of oxidative stress (ex vivo LDL oxidation, plasma total antioxidant status and ORAC, and lymphocyte single cell gel electrophoresis) in healthy overweight subjects. Twelve participants completed a 15-day run-in period followed by a 15-day intervention with a daily intake of 3 g guaraná seed powder containing 90 mg (+)-catechin and 60 mg (-)-epicatechin. Blood samples were taken on the first and last day of the intervention period, fasting and 1 h post-dose. The administration of guaraná increased plasma ORAC, while reducing ex vivo LDL oxidation (only in the first study day) and hydrogen peroxide-induced DNA damage in lymphocytes, at 1 h post-dose. Plasma catechin (0.38 ± 0.12 and 0.44 ± 0.18 nmol mL-1), epicatechin (0.59 ± 0.18 and 0.64 ± 0.25 nmol mL-1) and their methylated metabolites were observed at 1 h post-dose but were almost negligible after overnight fasting. The activities of catalase (in both study days) and glutathione peroxidase (in the last intervention day) increased at 1 h post-dose. Furthermore, the activity of both enzymes remained higher than the basal levels in overnight-fasting individuals on the last intervention day, suggesting a prolonged effect of guaraná that continues even after plasma catechin clearance. In conclusion, guaraná catechins are bioavailable and contribute to reduce the oxidative stress of clinically healthy individuals, by direct antioxidant action of the absorbed phytochemicals and up-regulation of antioxidant/detoxifying enzymes.

Be well!

JP

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